Machine for cutting concave surfaces



Get. 23, 1928.

. 1,688,781 J. E. BRANSON momma FOR CUTTING CONCAVE SURFACES Filed July31, 1925 2 Sheets-Sheet 1 Oct. 23, 1928.

J. E. BRANSON MACHINE FOR CUTTING CONCAVE SURFACES Filed July 31, 1925 2Sheets-Sheet 2 Patented Oct. 23, 1928.

UNITED STATES JAMES E. BRANSON, F CINCINNATI, OHIO.

MACHINE FOR CUTTING CONCAVE SURFACES.

Application filed July 31, 1925. Serial No. 47,186.

This invention relates generally to ma chines for cutting concavesurfaces and par ticularly for concaving the tops of shoe heels,especially heels made of maple and other hard woods.

In the manufacture of wooden shoe heels, concaving the top is,customarily, the final operation in bringing the heel to its final formbefore applying the covering material of i0 leather, celluloid or cloth.The usual practice is to so concave the top of the heel that a fiatedgedmargin about 1 16th inch wide remains from the plane surface whichcomprises the top of the block prior to concaving. For the H3 sake ofneat appearance, it is desirable that the edge of the cut made by theconcaving tool shall conform with the edge of the outer contour of theheel top. As this contour is curvilinear, and the radius of curvaturethereof is changing from one portion to another, some means oftraversing the work or the cut ter so that either one or the other willfollow the desired path is essential. The operation of concaving hasbeen customarily ac- ).5 complished with a rotary cutter, the cuttingedge of which has been ground to the desired curvature in a plane atright angles to the surface to be cut. Ordinarily, the cutter has beenrevolx 'ed in a fixed plane, and the heel has been 110 traversed beneaththe cutter to form the desirable concave surface. In concaving shoeheels by methods heretofore in use, a combination of levers and guidingcams of large radii, has been employed, the work being as traversedbeneath the cutter by manual means. The heel must be traversed under thecutter from front to back and returned over the same path withoutcutting and then traversed under the cutter a second time to 4m trim outthe small. amount of material remaining. Should it be attempted to cuton returning from the first cut, as from back to front, the cutter willtear the surface. The manual methods heretofore employed have oftenresulted in a rough or washboard surface due to the unsteady feed, andthe edge of the out being wavy and unsightly, and it is the object of myinvention to overcome these cutting defects. It is also an object of m.my invention to increase the output per operative, and to produce aproduct that is uniform. Another object of my invention is to provide amaster cam by means of which, through auxiliary mechanism, the heel may62 be guided in the proper path beneath the cut-- ter. further object ofmy invention is the provision of automatic means of clamping the workbefore, and automatically releasing it after it has been processed. Withthese and other objects not specifically mentioned in v ew, theinvention consists of certain co1n binations, constructions and partswhich will be hereinafter described and specifically pointed out in theclaims hereunto appended.

In the accompanying drawings whichform a part of this specification:

F igure 1 is a perspective View of one style of wooden heel for shoes,the top of which has been concaved by amachine constructed in accordancewith my invention.

Figure 2 is a plan view of a machine constructed in accordance with theinvention showing the various parts and their relation one to the other.

F lgure 3 is development of the drum cam 3'? of Figure 2.

Figure 4 is a fragmentary plan view of the mechanism of the work slideand the parts immediately subsidiary thereto.

Figure 5 is an elevation of the work slide and related mechanism,partially in section, the section being taken along the line 55 ofFigure 4.

Figure 6 is a plan of a block upon which has been drawn an outline ofthe master cam 57 In my invention the heel to be processed is clamped toa reciprocating slide, adapted to traverse the heel beneath a suitablerevolving cutter. The reciprocating slide is mounted on a pivoted slidecarrier, adapted to swing around the pivot in a direction transverse tothe longitudinal movement of the slide. The

heel, in its traverse beneath the cutter, may thus be constrained tofollow either a straight or a curvilinear path at the will of theoperator, or it may be constrained to follow a predetermined path, beingguided therein by means of master cam. which has been suitably arrangedin connection with the slide.

In the preferred construction, as shown in the accompanying drawings,the master cam is attached to the work slide, and on the end oppositethat to which the work is attached. As the slide progresses beneath thecutter, the master cam is broughtinto contact with a roller to which itis held by spring pressure, and the slide is swung to one side causingthe heel in process to follow a curved path determined by the contour ofthe master cam. As the center of the roller and the axis of the cutterare equi-distanthorizontally from the center of the slide carrier pivot,the path followed by the heel is a substantial duplicate of the contourcurve of the master cam. Therefore, the contour of the master cam may begenerated directly fronrthe contour of the heel top, as will behereinafter described.

Referring to the drawings, 7 represents the base or table of the machineupon which all the operating mechanism is mounted. The cutter 8 isattached to the cutter shaft 9, and the shaft is, in its turn, mountedin the bearings 10 and 11. Midway between the bearings and attached tothe shaft is a pulley 12 on-which is the belt 13, through the medium ofwhich the cutter is driven from any convenient source of power as, forexample, an electric motor. The work slide 14 is adapted to bereciprocated in a direction substantially at a right angle to the axisof the cutter shaft 9, and beneath the cutter 8, and is mounted on theslide carrier 15 to which it is fitted by means of suitable guideways16, these ways being of the same general. form as are employed for thecross-slide of an engine lathe. The carrier 15 is pivotally mounted onthe bed 7 by means of the pivot pin 17 attached thereto and preferablymade a part thereof as shown in the drawings. The pivot pin is adaptedto turn in the bearing 18, which may conveniently be a part of the base7. The weight of the slide and the carrier is suppprted by circular ways19 on the base, corresponding ways registering therewith being a part ofthe carrier as indicated at 20. The carrier with the slide is retainedin a midposition with the median line of these parts at a right angle tothe axis of the cutter, by means of the springs 21 and 22.

:The inner ends of these springs bear against the ears 23, 24 forming apart of the carrier 15. The outer ends of springs 21 and 22 bear againstthe inner ends of tension screws 25, 26, the screws being threaded inthe abutment !blocks 27, 28, bolted to the base 7, the screws beingadapted to be locked in position by 'means of. the internally threadedcollars 29,

At the rear of the base 7 is a shaft 31,

which is driven at a desired speed preferably about R. P. M. through themedium of a worm reduction gear which is indicated at 32. As this gearis of the usual conventional type and well known to those skilled .inthe art, no details of its construction are shown. This gear is mountedon a shelf 7' of the base which is stepped down from the main surface.The worm shaft, which forms the high speed member of the reducing gearis shown at 33. It is supported at its outer 37, which is secured to theshaft. The cam 37 is provided with a groove 38, the form of the groovebeing shown in the development in Figure 3, which will be described indetail later. A lever 39, composed of the short arm 39 and the long arm39", is pivotally mounted on the frame or base 7 by means of the fuicrumpin 40. The rocker arm has attached thereto on the outer end of theshort arm 39, a roller 41 engaging the sides of the groove 38. On theextreme outer end of the arm 39 I have provided a rectangular guideway42 to which there is slidably fitted a rectangular block 43, of whichthe corners only may be seen. The block 43 is bored to receive the pin44 which is fixed to the slide 14.

Bolted to the slide is aheel chuck or holding fixture comprised of abase 45, a fixed jaw 46, and a movable jaw 47. The jaws are fitted withinner faces 46' and 47 of babbitt or other metal of low melting pointwhich are formed by casting with a sample of the heel clamped in a mold,the metal being poured around the heel. A heel in its finished form,without the covering, is shown in Figure 1. The same style of heel inplace in the chuck is shown in Figure 2 at 48, and a larger heel with anover-hanging top at 48 in Figures 4 and 5. The movable member 47 of thechuck is pivoted to the base by means of the pin 49, and it isextendedinto an arm 47 to receive the stop screw 50. The jaws are, normally,held together to grasp the work by the spring 51 suitably attached tothe jaws. The base 45 is fitted with four set screws 52, secured withsuitable lock nuts 53, and the base 45 is held to the slide with T-bolts 54, the heads of the bolts being fitted to the T-slot 55 in theslide 14. The set screws serve to adjust the base 45 both as to to itsheight and to the proper angle of inclination to conform to therequirements of the heel in process, to bring the heel in correctrelation to the cutter, in order that the cut may be made the properdepth and contour, in the heel.

Projecting upwardly from the slide carrier 15 and fixed thereto, is astop 56 adapted to contact with the screw 50 just as the slide isapproaching the end of its longer outward stroke, which is the strokethat approaches that edge of the base shown at the lower edge of Figure2 in the drawing. This contact of screw 50 with stop 56 opens jaw 47 andunclamps the work, permitting its removal by the operator, and thejawremains in the open position for a length of time sufficient to per--mit the insertion of an unfinished heel.

Fixed to that end of the slide 14 opposite the end in which the heel isheld, is a master cam composed of the wooden center piece 57, surroundedby a metal strap 58, which is attached to the block 57 by means of abolt 59 passing through both the strap and the block. The purpose of thestrap is to provide a harder Jon wearing surface than would be providedby the edge of the wooden center, were the latter required to contactdirectly with the roller 65. The roller is adapted to remain in asubstantially fixed position during the period of contact with the outersurface of the strap 58, and the master cam is attached to the raisedpad 60, forming a part of the slide 14, by means of the clamp 61, andthe bolts 62 which are of the Thead type and. are so arranged that theheads of the bolts are held in the T-slot 63.

The roller 65 mounted upon a pin 66 attached to the end of the plunger6'? slidably mounted in the block 68. The block is clamped to theparallel bars 69 69 by means of the bolt to brackets 7l?l fixed to thebase. A spring 70, mounted. in compression between the block 68 and thehead 67 of the )lunger 67, has a tendency to force the plunger upward.Supported on brackets l 1'. l fixed to base 7 is rocker upon which arepivoted the bell-crank levers 'Z3-73 comprised of the short arms Z+l: land the lon or arms 75. The outer ends of the arms 74.7 l contact withthe tops ot the plung" 67 B? and the outer ends of the arms 75- contactwith cam blocks 76 as shown in Fi ure 5. The block 76 is bolted to adisk 77, the disk being attached to the shaft 81. The block 76 isrotated with shaft 31 in the direction of the arrow, thrusting the arm75 outward as it passes thereunder, rotating the love" around the shaft72, the arm 7% being swung downward, forcing the plunger 6'? downwardand thrusting the roller 65 into the path of the master cam. A secondroller (35, which is in dicated in dotted lines in Figure 4-, ismanipulated in a like manner by means of a second cam block 7 6 throughthe medium of the rockor arm 7 8 and the plunger 67.

For convenience of reference, the path of the slot 38 provided in thesurface of the cam 37 is divided into sections in the developmentthereof as shown in Figure 3, and the sections indicated by letters. Thedirection of rotation of the cam is indicated by the arrow and thedirection of the movement of the roller ll slidabiy engaged in the slot38 is indicated by the double arrow LL. That portion of the slot 38which is parallel to the side of the cam as indicated by ar a. gives nocross movement to the roller 41. As the section indicated at b of theslot passes beneath the roller, the latter is moved in the direction L,swinging the lever arm 39 in Figure 2 to the right, thus giving theslide 1 2 its first inwarc stroke. As the section shown at c of. theslot passes beneath roller 41, the roller is moved in the direction L,and the arm 39 is swung to the left, but not to the extent of returningit to the position corresponding to that 0811;- pied when the roller isengaged in section :1, of the slot. As the section indicated at (Z ispassed by the roller, the roller is again moved in the direction of thearrow L, and the arm 39 is swung to the right for a second time. Thethird section shown at c of the slot 38 compels the roller to follow thedirection L and the roller reaches that portion of the slot indicated ata in Figure 3, and shown at the right side of the figure. As thisportion of the groove and that portion marked a at the left side of thefigure are continuations, one of the other, the movement of the rollerprodured by one revolution of the cam 37 is completed when the rollerenters section a from section c.

The block 5" of Figure 6 is a blank from which is cut the center 5? ofthe master cam. This is shown in outline by means of the heavy line 0.In determining the era ct sha a e of the curved portion of the camoutline, the shoe heel to be concaved by the aid of the cam is laid topdown on the block and the outline of the top is transferred to the blockby erawing a sharp point around the outer edge of the heel top, therebysecuring line C mustaarallel the curve 0 being at a distance therefromequal to the flat'edgeE, Figure 1, plus the thickness of the strap 58. For example, the width of the flat surface E is about inch and thethickness of the strap 58 about inch, making a total of inch. setting apair of dividers with their points 2 inch apart, it is a simple matterto generate the curved portion of the outline 0 directly from the curve0.

The operation of the machine is as follows: lVith the slide clear backand the roller 41 in the section a of the slot 38, the chuck 4-7 is heldback against the tension of the spring 51 by the stop 56, and is in theposition indicated by the broken lines 47, Figured. The operator sets ashoe heel to be concaved on the plate 45 and against the inner fixed jaw46, holding it in place until the continued movement of cam 37 bringsthe roller into section Z) of the slot 38, and the slide moves towardthe cutter a sulficient distance to release spring 51 and permit it topull jaw 4? against the heel, clamping it in place. As section I) of theslot 38 moves beneath the roller 4-1, the

arm 39 is swung to the right, the arm 39" being swung toward the top ofthe figure, the slide 14 starts toward the back of the base which is atthe top of Figure 2, and the heel 48 approaches the cutter 8. During thefirst portion of this, the first stroke of the slide 14:, the movementof the slide is in a direction at a right angle to the axis of thecutter shaft 9, being constrained to follow this path by the guideways16 on the carrier 15 and the springs 21, 22, which hold the median lineof the carrier in a positionata right angle to the axis of. the shaft 9.As the slide proceeds on its first stroke the roller 65 is depressedinto the path of the master cam 57 through the interaction of the camblock 7 6, the rocker arm 73 and the plunger 67 to which the roller 65is the curve 0. The out-- attached. The roller is held in this depressedposition, as the surface of the block 76 slides beneath the lower end oflever 75, and only so long as the block and the lever are in contact.Further progress of the slide 2 brings the heel beneath the cutter 8,and the surface of the cam strap 58 into contact with roller 65, thecutter concaving the top of the heel and the slide 14 deflected from arectilinear path by means of the master cam, which is held to the rollerby the pressure of the spring 22, as illustrated in Figure 4. Thedeflection of the slide 14 and its carrier 15 causes the cutter 8 to socut out the top of the heel that the edge of the cut, shown on the leftin Figure 2, and shown toward the top in Figure 4, must follow a curvedpath which is a replica of the curved edge 58 of the master cam. Just asthe end of the stroke corresponding to section b of the cam groove 38 iscompleted, the block 7 6 passes from under the lever 7 5, and the leverslips over the corner w of block 76. Immediately, the spring 7 0 forcesthe plunger 67 upward and the roller 65 is withdrawn from the path ofthe master cam 57. Roller 41 now enters sec tion 0 of slot 38, and thearm 39 is swung to the left, starting the slide 14 on its first backwardstroke. There being nothing in the path of the cam 57, the'springs 21,22 hold the carrier and the slide in a central position and the heel isreturned from beneath the cutter along a line at a right angle to theaxis of shaft 9. The length of this stroke of the slide is about 65 percent of the first forward stroke, and is not long enough to bring thescrew 50 into contact with the stop 57. Hence the chuck does not open.As section d of the slot 38 passes beneath the roller, the arm 39 isagain swung to the right and the heel is traversed toward the cutter 8for the second time. Just as this stroke is started, cam 76' (Figure 2)swinging lever arm 75 outward, depresses plunger 67 and roller 65 ispushed into the path of the master cam 57, and the slide with thecarrier is swung in a clockwise direction as seen from above, or in thedirection opposite to that shown in Figure 4. The spring 21 is nowcompressed, and it is the pressure of this spring that holds the cam 57against the roller 65. The concaving is now completed along the side ofthe heel opposite to that cut during the first stroke. 1: s the roller41 is about to enter section 6 of slot 38, block 76' passes from underthe end of lever 75, releasing the plunger 67 and roller 65 is withdrawnfrom the path of the master cam 57, allowing theslide to return along aline at a right angle to the axis of shaft 9. This stroke is the samelength as the first forward stroke, and just as the end of this stroke'is approached, the screw 50 contacts with stop 56, opening the chuckand releasing the finished heel. The roller 41 has now entered section aof slot 38, and the slide 14 dwells at The output per hour is limitedonly by the dexterity of the operator in removing the finished work andreplacing it with an unfinished heel. The facility with which the cammay be developed from the heel to be processed, and the ease with whichthe work mayv be set to the proper height, inclination and position withreference to the cutter, is a great improvement over methods and devicesformely in' use.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is

1. In a machine for cutting concave surfaces, a main frame, a pair ofbearing blocks attached to the frame and extending upwardly therefrom, ashaft in the bearing blocks, a rotary forming cutter on the shaft andextending thereon over the frame, a work slide beneath the cutter, theslide adapted to be reciprocated in a direction substantially at a rightangle to the axis of the cutter shaft, work holding means disposed inone end of the slide, a master cam on the end of the slide opposite thework holding means, a carrier for the slide, the carrier adapted toguide the slide in a direction normally at a right angle to the axis ofthe cutter shaft, the carrier pivotally mounted on the frame, and meansadapted to yieldingly retain the carrier with the median line of thecarrier at a right angle to the axis of the cutter shaft.

2. In a shoc-heel concaving machine, a forming cam, the forming camcomprising luu a central block portion, the top and the bottom of thecentral portion being plane surfaces and parallel one to the other, theedges of the block joining the top and the bottom surfaces being formedin the major part of a curve generated by laying a sample heel invertedon the block, following the contour with a marking instrument, therebytransferring the outline of the heel top directly to the cam block, thecam being completed by sawing out the contour on a line parallel to theoutline of the heel top transferred thereto as described.

3. In a shoe heel concaving machine, a

by the'aid of the contour of the forming cam, and means for attachingthe forming cam to the work slide.

4. In a shoe-heel concaving machine, a main frame, a forming cutter, acutter shaft for retaining the cutter, th shaft mounted on the frame, areciprocating work slide, a carrier for the work slide, the carrierpivotally mounted on the frame, a heel holding filiture attach ed to theslide, a forming cam also attached to the slide, spring elements adaptedto maintain the median line of the carrier and of the slide normally ata right angle to the axis of the cutter shaft, retractable plungers,rollers on the lower ends of the plungers, fixed guides for theplungers, means for periodically reciprocating the plungers whereby therollers thereon are thrust into the path of the forming cam, means forretracting the plungers and withdrawing the rollers from the path of theforming cam, the rollers being thrust into the path of the cam for thepurpose of so deflecting the forming cam, the work slide to which thecam is attached, and the heel attached to the work slide so that theedge of the cut on the heel top will conform substantially to thecontour of the cam, while the roller is in contact therewith, and thepath of the heel top will be along a line at a right angle to the axisof the cutter shaft when both rollers are retracted.

5. In a shoeheel concaving machine, a main frame, a cutter rotatablymounted on the frame, a reciprocating work slide, a carrier for theslide, means of aligning the slide on the carrier, the carrier pivotallymounted on the frame, means for reciprocating the slide, said meanscomprising a cylindrical cam, a rocker pivoted to the frame carrying aroller adapted to traverse the cam groove, the other contour of oneside. of the heel top, means for withdrawing the heel a right angle tothe axis of the cutter from beneath the cutter,

means of'moving the slide again beneath the cutter said means adapted toalign the edge of the second cut parallel to the outer contour of theotherside of the heel top, means of again withdrawing the heel frombeneath the cutter in a path at a right angle to the axis of the cutter,and means of releasing the heel from the Work slide.

'7. in a machine for concaving the tops of shoe-heels, a rotatingforming cutter, means for passing the heel beneath the cutter along apath substantialy parallel to the outer edge of one side of the heeltop, means for withdrawing the heel along a path at a right angle to theaxis of the cutter, said first mentioned means operable for againpassing the heel underneath. the cutter along a path substantiallyparallel to the other side of the heel top, and said second mentionedmeans operable for again withdrawing the heel along a path at a rightangle to the axis of the cutter.

JAMES E. BRANSON.

